CERN Accelerating science

Article
Title	Mono Energetic Beams from Laser Plasma Interactions
Author(s)	Geddes, Cameron G ; Cary, John R ; Esarey, Eric ; Leemans, Wim ; Nieter, Chet ; Schröder, Carl B ; Toth, Csaba ; Van Tilborg, Jeroen
Affiliation	(CIPS, Boulder, Colorado; Tech-X, Boulder, Colorado) ; (LBNL, Berkeley) ; (LBNL, Berkeley, California; TUE, Eindhoven) ; (Tech-X, Boulder, Colorado)
Publication	2005
In:	21st IEEE Particle Accelerator Conference, Knoxville, TN, USA, 16 - 20 May 2005, pp.69
Subject category	Accelerators and Storage Rings
Abstract	A laser driven wakefield accelerator has been tuned to produce high energy electron bunches with low emittance and energy spread by extending the interaction length using a plasma channel. Wakefield accelerators support gradients thousands of times those achievable in RF accelerators, but short acceleration distance, limited by diffraction, has resulted in low energy beams with 100% electron energy spread. In the present experiments on the L’OASIS laser,* the relativistically intense drive pulse was guided over 10 diffraction ranges by a plasma channel. At a drive pulse power of 9 TW, electrons were trapped from the plasma and beams of percent energy spread containing >200pC charge above 80 MeV and with normalized emittance estimated at < 2 pi -mm-mrad were produced.** Data and simulations (VORPAL***) show the high quality bunch was formed when beam loading turned off injection after initial trapping, and when the particles were extracted as they dephased from the wake. Up to 4TW was guided without trapping, potentially providing a platform for controlled injection. The plasma channel technique forms the basis of a new class of accelerators, with high gradients and high beam quality.